The present invention is directed to electrical connectors and, more particularly, to an electrical connector having improved means for sealing the connector from moisture and other harmful substances.
For several years demand has been increasing in the transportation, communication and data processing industries for electrical connectors capable of withstanding severe environmental conditions retaining or even improving their serviceability. A need for such connectors is particularly acute in the aerospace industry where reliability in extreme environments and serviceability are most important. In response to this demand, a variety of connectors have been developed having means to effectively seal the contacts within the connector shell while still enabling removal and reinstallation of an individual contact should maintenance of the connector so require. One approach to this problem has been to seal the rearward or conductor-receiving end of the connector components with an elastomeric insert or grommet, the individual contacts being forced through restrictive apertures in the grommet during installation or removal. Typical examples of such connectors are illustrated in U.S. Pat. Nos. 3,336,569; 3,512,119; 3,786,396; and 3,960,428. While these connectors provide adequate sealing in those applications where contacts are utilized in all of the connector's contact pockets, they do not properly seal the interior of the connector when all the available contact pockets are not in use. Moisure, for example, may enter and permeate the interior of the connector through any of the unused pockets.
To overcome this problem prior art connectors have been provided with miniature plugs which are inserted into the unused pockets. This approach, however, is costly, both in terms of manufacture and assembly, and is dependent upon the reliability of the assemblor who must insure that a plug is inserted within every empty pocket. Moreover, since the plug is a separate component, if it is not properly installed the seal may be ineffective which, in turn, may give rise to field failure of the connector.
Another suggested approach for resolution of this problem has been the application of a coating to the rearward exterior of the grommet. The coating may be applied either before or after the connector has been assembled to the contact terminated conductors, but conventional practice is to apply the coating prior to assembly. This technique, however, is both time consuming and labor intensive, making it costly and unappealing to the connector user. Once again, the integrity of the seal is dependent upon the proper application of the coating and, as a result, the field reliability of the connector is not ideal.